Vocabulary acquisition represents a major challenge in foreign language learning. Research has demonstrated that gestures accompanying speech have an impact on memory for verbal information in the speakers' mother tongue and, as recently shown, also in foreign language learning. However, the neural basis of this effect remains unclear. In a within-subjects design, we compared learning of novel words coupled with iconic and meaningless gestures. Iconic gestures helped learners to significantly better retain the verbal material over time. After the training, participants' brain activity was registered by means of fMRI while performing a word recognition task. Brain activations to words learned with iconic and with meaningless gestures were contrasted. We found activity in the premotor cortices for words encoded with iconic gestures. In contrast, words encoded with meaningless gestures elicited a network associated with cognitive control. These findings suggest that memory performance for newly learned words is not driven by the motor component as such, but by the motor image that matches an underlying representation of the word's semantics.

It has previously been demonstrated that enactment (i.e., performing representative gestures during encoding) enhances memory for concrete words, in particular action words. Here, we investigate the impact of enactment on abstract word learning in a foreign language. We further ask if learning novel words with gestures facilitates sentence production. In a within‐subjects paradigm, participants first learned 32 abstract sentences from an artificial corpus conforming with Italian phonotactics. Sixteen sentences were encoded audiovisually. Another set of 16 sentences was also encoded audiovisually, but, in addition, each single word was accompanied by a symbolic gesture. Participants were trained for 6 days. Memory performance was assessed daily using different tests. The overall results support the prediction that learners have better memory for words encoded with gestures. In a transfer test, participants produced new sentences with the words they had acquired. Items encoded through gestures were used more frequently, demonstrating their enhanced accessibility in memory. The results are interpreted in terms of embodied cognition. Implications for teaching and learning are suggested.

At present, it is largely unclear how the human brain optimally learns foreign languages. We investigated teaching strategies that utilize complementary information ("enrichment"), such as pictures or gestures, to optimize vocabulary learning outcome. We found that learning while performing gestures was more efficient than the common practice of learning with pictures and that both enrichment strategies were better than learning without enrichment ("verbal learning"). We tested the prediction of an influential cognitive neuroscience theory that provides explanations for the beneficial behavioral effects of enrichment: the "multisensory learning theory" attributes the benefits of enrichment to recruitment of brain areas specialized in processing the enrichment. To test this prediction, we asked participants to translate auditorily presented foreign words during fMRI. Multivariate pattern classification allowed us to decode from the brain activity under which enrichment condition the vocabulary had been learned. The visual-object-sensitive lateral occipital complex (LOC) represented auditory words that had been learned with pictures. The biological motion superior temporal sulcus (bmSTS) and motor areas represented auditory words that had been learned with gestures. Importantly, brain activity in these specialized visual and motor brain areas correlated with behavioral performance. The cortical activation pattern found in the present study strongly supports the multisensory learning theory in contrast to alternative explanations. In addition, the results highlight the importance of learning foreign language vocabulary with enrichment, particularly with self-performed gestures.